Steel-concrete composite beam and construction method using same

ABSTRACT

A steel-concrete composite beam includes a long rectangular steel frame; concrete members installed at only both ends of the steel frame, excluding a center portion thereof; a prestressable reinforcement buried in the concrete member; and a stirrup reinforcement arranged to the concrete member with a regular gap thereto to surround a lower flange of the steel frame.

TECHNICAL FIELD

The present invention relates to a steel-concrete composite beam and aconstruction method using the same. More particularly, the presentinvention relates to a steel-concrete composite beam in which concretemembers are installed at only both ends of the beam, excluding thecenter portion thereof, to reduce self weight and in which a supportmember is provided at a steel frame so that a deck plate may beinstalled thereto during slab construction for convenient installationand construction of the deck plate, and a construction method using thesame.

BACKGROUND ART

Korean Patent Registration No. 0761786 discloses a concrete compositeshape steel beam in which a steel frame with an H-shaped section and aconcrete are integrally formed to reduce a height of one story.

This concrete composite shape steel beam is precast at a factory andthen transported to a construction spot to be assembled there.

However, the concrete composite shape steel beam disclosed in the abovepatent has H-shaped steel and concrete member over the entire length ofthe beam, resulting in high material costs and difficulty in handlingand construction due to heavy weight.

Korean Patent Registration No. 0808057, entitled “a composite member anda construction method of a structure using the same”, discloses acomposite member in which structural steels are installed at only bothends of a concrete member to reduce self weight and decreaseconstruction cost.

However, the composite member configured as above has a relatively weakstrength since a steel frame is not provided to the center portionthereof. In addition, if the beam has great length, it is not easy toendure a stress moment applied in a vertical direction. Thus, a lowerstructure such as a supporting post or a support should be installedseparately.

DISCLOSURE Technical Problem

The present invention is designed to solve the problems of the priorart, and therefore it is an object of the present invention to provide asteel-concrete composite beam, which is configured to sufficientlyresist a bending moment during construction work and have a reducedoverall weight so as to ensure easy handling and construction.

Another object of the present invention is to provide a steel-concretecomposite beam having an improved configuration to ensure easyinstallation of a deck plate during slab construction.

Furthermore, another object of the present invention is to provide amethod for constructing a building by using the steel-concrete compositebeam as mentioned above.

Technical Solution

In order to accomplish the above object, the present invention providesa steel-concrete composite beam, which includes a long rectangular steelframe; concrete members installed at only both ends of the steel frame,excluding a center portion thereof; a prestressable reinforcement buriedin the concrete member; and a stirrup reinforcement arranged to theconcrete member with a regular gap thereto to surround a lower flange ofthe steel frame.

Preferably, the concrete member is formed to bury a part of a lower endof the lower flange and a web of the steel frame so that an upper flangeof the steel frame is located to be higher than an upper surface of theconcrete member. The steel-concrete composite beam further comprises asupport member formed to extend from the center portion of the steelframe, where the concrete member is not formed in a lateral direction,and an upper surface of the support member has the same height as theupper surface of the concrete member.

More preferably, the support member includes a fixed side fixed to theweb of the steel frame; and an installing side extending in parallelwith the upper flange in a lateral direction of the steel frame.

As an alternative, the concrete member is formed to bury even an upperflange of the steel frame so that an upper surface of the upper flangeof the steel frame is located at the same height as an upper surface ofthe concrete member.

In another aspect, the present invention provides a method forconstructing a building, which includes installing a pillar member andconnecting the above steel-concrete composite beam to the pillar member.

Advantageous Effects

The steel-concrete composite beam according to the present inventionallows easy handling and transportation due to its light weight sinceconcrete members are partially formed at only both ends of the beam,excluding the center portion thereof.

Nevertheless, a steel frame is provided over the entire length of thesteel-concrete composite beam of the present invention, which allows thebeam to effectively resist a bending moment concentrated on the centerportion and give sufficient design strength.

Further, according to the steel-concrete composite beam of the presentinvention, a deck plate may be installed to a support member or directlyinstalled to an upper flange of the steel frame during slabconstruction, which ensures very convenient construction and effectivelylowers the height of a story.

DESCRIPTION OF DRAWINGS

Other objects and aspects of the present invention will become apparentfrom the following description of embodiments with reference to theaccompanying drawing in which:

FIG. 1 is a perspective view schematically showing a steel-concretecomposite beam according to a preferred embodiment of the presentinvention;

FIG. 2 is a front view schematically showing the steel-concretecomposite beam according to the preferred embodiment of the presentinvention;

FIG. 3 is a plane view schematically showing the steel-concretecomposite beam according to the preferred embodiment of the presentinvention;

FIG. 4 is a sectional view taken along the line A-A′ of FIG. 1;

FIG. 5 is a sectional view taken along the line B-B′ of FIG. 1;

FIG. 6 is a perspective view schematically showing a steel-concretecomposite beam according to another embodiment of the present invention;

FIG. 7 is a front view schematically showing the steel-concretecomposite beam according to another embodiment of the present invention;

FIG. 8 is a plane view schematically showing the steel-concretecomposite beam according to another embodiment of the present invention;

FIG. 9 is a sectional view taken along the line C-C′ of FIG. 6;

FIG. 10 is a perspective view showing an example in which thesteel-concrete composite beam according to the preferred embodiment ofthe present invention is connected to a pillar member;

FIGS. 11 and 12 illustrate that a slab is constructed by using thesteel-concrete composite beam according to the preferred embodiment ofthe present invention; and

FIG. 13 is a front view showing a steel-concrete composite beamaccording to another embodiment of the present invention.

BEST MODE

FIGS. 1 to 5 schematically show a steel-concrete composite beamaccording to a preferred embodiment of the present invention. FIG. 1 isa perspective view showing the steel-concrete composite beam accordingto the present invention, FIG. 2 is a front view thereof, FIG. 3 is aplane view thereof, and FIGS. 4 and 5 are sectional views respectivelytaken along lines A-A′ and B-B′ of FIG. 1.

Referring to FIGS. 1 to 5, the steel-concrete composite beam accordingto the present invention includes a long rectangular steel frame 10, andconcrete members 12 installed at both ends of the steel frame 10,excluding a center portion of the steel frame 10.

The steel frame 10 is long enough to be hanging between pillars of abuilding to be constructed. The length of the steel frame 10 may bechanged variously if necessary.

Also, as shown in the sectional views of FIGS. 4 and 5, the steel frame10 is a steel with an I- or H-shaped section. The steel frame 10includes a pair of upper and lower flanges 14 and 16 formed in parallel,and a web 18 connected between the upper and lower flanges 14 and 16.

According to the present invention, the concrete member has a hexahedralor another polyhedral shape and is installed at only both ends of thesteel frame 10, excluding the center portion thereof. In thisembodiment, the concrete member 12 is formed so that the lower flange 16and the web 18 of the steel frame 10 are partially buried therein. Thus,the upper flange 14 of the steel frame 10 is located to be higher thanthe upper surface of the concrete member 12.

Though not shown precisely in the drawings, a plurality of stud membersis formed at the side of the web 18 buried in the concrete member 12 soas to improve a coupling force between the web 18 and the concretemember 12.

Also, the front end of the steel frame 10 is not buried in the concretemember 12 but protrudes out of the concrete member 12 so that the frontend of the steel frame 10 may be connected to a pillar member asexplained later. For this purpose, a plurality of coupling holes 20 maybe formed in the front end of the steel frame 10.

In the present invention, the length of the center portion of the steelframe 10, to which the concrete member 12 is not installed, may besuitably set in consideration of the length and weight of the beam.Preferably, the length of the center portion of the steel frame 10 isgreater than the sum of the lengths of the concrete members 12 installedat both ends of the steel frame 10.

For example, a ratio of the length of the center portion to the entirelength of the steel-concrete composite beam may be 0.5 to 0.8, but thepresent invention is not limited thereto.

Preferably, the steel-concrete composite beam of the present inventionincludes at least one prestressable reinforcement 22 arranged in alongitudinal direction thereof.

More preferably, the part of the prestressable reinforcement 22 buriedin the concrete member 12 may be buried in a prestressable state by apre-tensioning method.

In this case, the sectional area of the concrete member 12 may beincreased, and the increased sectional area may give an effectiveresistance against a tensile stress caused by a load.

As another alternative, the prestressable reinforcement may not beprovided to the center portion, excluding the concrete members 12, asshown in FIG. 13.

Also, the prestressable reinforcement may be buried in the concretemember 12 while being bent upwards, as shown by dotted lines in FIG. 13.

In addition, a stirrup reinforcement 24 is installed to the concretemember 12 with a regular gap thereto. The stirrup reinforcement 24 isburied in the concrete member 12 to surround the lower flange 16 of thesteel frame 10. Both ends of the stirrup reinforcement 24 are exposed onthe upper surface of the concrete member 12.

Preferably, the stirrup reinforcement 24 is arranged to be in contactwith the prestressable reinforcement 22. More preferably, the stirrupreinforcement 24 is arranged to surround the lower flange 16 of thesteel frame 10 and the prestressable reinforcement 22.

The steel-concrete composite beam according to the present inventionincludes a support member 26 for allowing a deck plate to be installedduring slab construction.

Specifically, the support member 26 extends from the center portion ofthe steel frame 10, where the concrete member 12 is not formed in alateral direction. More specifically, the support member 26 is anL-shaped angle as shown in FIG. 5, which includes a fixed side 26 afixed to the web 18 of the steel frame 10 and an installing side 26 bextending in parallel with the upper flange 14 in a lateral direction ofthe steel frame 10.

At this time, the upper surface of the support member 26, namely theupper surface of the installing side 26 b is at the same height as theupper surface of the concrete member 12. As described later, the deckplate may be installed to the upper surface of the support member 26 andthe upper surface of the concrete member 12 at the same time.

FIGS. 6 to 9 schematically show a steel-concrete composite beamaccording to another embodiment of the present invention. Here, likereference numerals designate like components with like functions incomparison to the former drawings.

The steel-concrete composite beam of this embodiment includes a steelframe 10 and concrete members 12′ formed at only both ends of the steelframe 10, excluding the center portion thereof.

Also, the concrete members 12′ are configured to bury even the upperflange 14 of the steel frame 10. At this time, the upper surface of theupper flange 14 of the steel frame 10 is located at the same height asthe upper surface of the concrete member 12′.

Since the upper flange 14 of the steel frame 10 is formed at the sameheight as the concrete member 12′ in this embodiment, a deck plate maybe installed on the upper surface of the upper flange 14 during slabconstruction. Thus, the upper flange 14 of the steel frame 10 plays thesame role as the support member 26 of the former embodiment. For thisreason, the steel-concrete composite beam of this embodiment does notneed a separate support member.

Therefore, the steel-concrete composite beam of this embodiment has asimple configuration and a decreased weight.

Now, a method for constructing a building by using the steel-concretecomposite beam according to the preferred embodiment of the presentinvention, which is configured as mentioned above, will be described.

The steel-concrete composite beam according to the present invention isprecast and fabricated at a factory. After the steel frame 10 and theprestressable reinforcement 22 as well as the stirrup reinforcement 24are arranged, the concrete members 12 may be placed at only both endsthereof to form a beam. At this time, the prestressable reinforcement 22may be buried in the concrete member 12 by means of a pre-tensioningmethod.

The steel-concrete composite beam fabricated as above is transported toa construction spot and then installed there.

First, prior to installing the steel-concrete composite beam, a pillarmember is installed at a location where a pillar of a building will beformed. The pillar member may be constructed by using H-shaped steel ora precast concrete pillar. In the following description and appendedclaims, the pillar member is defined to be inclusive of various kinds ofpillars such as H-shaped steel.

FIG. 10 shows that the pillar member 100 is installed by using H-shapedsteel. If the pillar member 10 is completely installed, thesteel-concrete composite beam of the present invention is connected tothe pillar member 100 subsequently.

For this purpose, a connection bracket 112 having a plurality ofcoupling holes 110 is installed to the pillar member 100 in advance.Thus, as shown in the figure, the front end of the steel frame 10 of thesteel-concrete composite beam according to the present invention isaligned to the connection bracket 112, and then coupling bolts 114 areinserted into the coupling holes 110 and 20 and fastened with nuts 116.

In another embodiment of the present invention, the steel-concretecomposite beam may be directly fixed to the pillar member 100 bywelding. In other words, the front end of the steel frame 10 may bewelded to the pillar member 100 directly or with a mediate member or anauxiliary member being interposed between them.

As described above, the steel-concrete composite beam may be connectedto the pillar member in various ways, without being limited to theabove.

If the steel-concrete composite beam is completely connected to thepillar member 10 as described above, a deck plate 130 is installed onthe composite beam and a slab reinforcement 132 is arranged thereon. Thedeck plate 130 plays a role of a mould for the slab. The deck plate 130is already well known in the art and thus not described in detail here.

According to the present invention, the deck plate 130 is installed tobe held by the edge of the upper surface of the concrete member 12 ofthe steel-concrete composite beam. At the same time, in the centerportion of the beam, the deck plate 130 is installed to be held on theupper surface of the support member 26, specifically, on the installingside 26 b. FIG. 11 shows the deck plate 130 installed on the uppersurface of the support member 26.

By the above procedure, the deck plate is installed to cover a regionbetween beams. In the steel-concrete composite beam of this embodiment,the upper surface of the concrete member 12 is located to be lower thanthe upper surface of the steel frame 10, which may reduce an entireheight of one story and a depth of a beam.

Further, if necessary, a mould may be suitably installed at theconnection region between the pillar member 100 and the beam.

Subsequently, if concrete is poured, placed and cured on the deck plate130, a slab using the steel-concrete composite beam according to thepresent invention is completely constructed.

FIG. 12 shows a process of constructing a slab by using thesteel-concrete composite beam according to the embodiment shown in FIGS.6 to 9.

Even in the case of the steel-concrete composite beam of thisembodiment, the deck plate 130 is installed on the edge of the uppersurface of the concrete member 12′.

Also, in this embodiment, the upper surface of the upper flange 14 ofthe steel frame 10 is located at the same height as the upper surface ofthe concrete member 12′. Thus, the deck plate 130 is directly installedto the upper surface of the upper flange 14 as shown in FIG. 12.

Finally, concrete is placed and cured in the same way as in the formerembodiment.

1. A steel-concrete composite beam, comprising: a long rectangular steelframe; concrete members installed at only both ends of the steel frame,excluding a center portion thereof; a prestressable reinforcement buriedin the concrete member; and a stirrup reinforcement arranged to theconcrete member with a regular gap thereto to surround a lower flange ofthe steel frame.
 2. The steel-concrete composite beam according to claim1, wherein the concrete member is formed to bury a part of a lower endof the lower flange and a web of the steel frame so that an upper flangeof the steel frame is located to be higher than an upper surface of theconcrete member, wherein the steel-concrete composite beam furthercomprises a support member formed to extend from the center portion ofthe steel frame, where the concrete member is not formed, in a lateraldirection, and wherein an upper surface of the support member has thesame height as the upper surface of the concrete member.
 3. Thesteel-concrete composite beam according to claim 2, wherein the supportmember includes: a fixed side fixed to the web of the steel frame; andan installing side extending in parallel with the upper flange in alateral direction of the steel frame.
 4. The steel-concrete compositebeam according to claim 1, wherein the concrete member is formed to buryeven an upper flange of the steel frame so that an upper surface of theupper flange of the steel frame is located at the same height as anupper surface of the concrete member.
 5. The steel-concrete compositebeam according to claim 1, wherein a front end of the steel frame is notburied in the concrete member but protrudes out, and a plurality ofcoupling holes is formed in the front end of the steel frame.
 6. Thesteel-concrete composite beam according to claim 2, wherein a front endof the steel frame is not buried in the concrete member but protrudesout, and a plurality of coupling holes is formed in the front end of thesteel frame.
 7. The steel-concrete composite beam according to claim 3,wherein a front end of the steel frame is not buried in the concretemember but protrudes out, and a plurality of coupling holes is formed inthe front end of the steel frame.
 8. (canceled)
 9. The steel-concretecomposite beam according to claim 4, wherein a front end of the steelframe is not buried in the concrete member but protrudes out, and aplurality of coupling holes is formed in the front end of the steelframe.
 10. The steel-concrete composite beam according to claim 1,wherein a length of the center portion of the steel frame, where theconcrete member is not formed, is greater than a sum of the lengths ofthe concrete members.
 11. The steel-concrete composite beam according toclaim 2, wherein a length of the center portion of the steel frame,where the concrete member is not formed, is greater than a sum of thelengths of the concrete members.
 12. The steel-concrete composite beamaccording to claim 3, wherein a length of the center portion of thesteel frame, where the concrete member is not formed, is greater than asum of the lengths of the concrete members.
 13. The steel-concretecomposite beam according to claim 4, wherein a length of the centerportion of the steel frame, where the concrete member is not formed, isgreater than a sum of the lengths of the concrete members.
 14. Thesteel-concrete composite beam according to claim 1, wherein a pluralityof stud members is formed at a side of a web of the steel frame, whichis buried in the concrete member.
 15. The steel-concrete composite beamaccording to claim 2, wherein a plurality of stud members is formed at aside of a web of the steel frame, which is buried in the concretemember.
 16. The steel-concrete composite beam according to claim 3,wherein a plurality of stud members is formed at a side of a web of thesteel frame, which is buried in the concrete member.
 17. Thesteel-concrete composite beam according to claim 4, wherein a pluralityof stud members is formed at a side of a web of the steel frame, whichis buried in the concrete member.
 18. A method for constructing abuilding, comprising: installing a pillar member; and connecting thesteel-concrete composite beam according to claim 1 to the pillar member.19. A method for constructing a building, comprising: installing apillar member; and connecting the steel-concrete composite beamaccording to claim 2 to the pillar member.
 20. A method for constructinga building, comprising: installing a pillar member; and connecting thesteel-concrete composite beam according to claim 3 to the pillar member.21. A method for constructing a building, comprising: installing apillar member; and connecting the steel-concrete composite beamaccording to claim 4 to the pillar member.